Nothing bad will happen... but it's better to remove your old one and install 2.06.
However make sure that your game folder _is not_ under Gaia's directory or you'll use all previously installed games.
You've been warned.
@alexdais: come on mate, there's plenty of tutorial everywhere, you can't hijack a topic like that. (hint: run gaia, insert BR, hit copy...)
PS3 Slim v3.55 + CFW Kmeaw - 250G/USB 1T
XBOX 360 Falconv3/Jtag - Liteon74 1.61 - 500G
Wii 4.2 + Cfg UsbLoader - USB 250G | NDS + M3 Real - SDHC 8G | NDS + R4i - SDHC 4G
PS2 + HDLoader - HDD 200G | PSX + PS Hacker